Improvement in joints for school-desks



THQMAS A. GALT 8:. GEORGE TRACY improvement in School Desk Joints.

No. 618,773. Patented Sep. 5.1871.

UNITED STATES PATENT QFFIGE.

THOMAS A. GALT AND GEORGE S. TRACY, OF STERLING, ILLINOIS.

IMPROVEMENT IN JOINTS FOR SCHOOL-DESKS.

Specification forming part of Letters Patent No. 118,773, dated September 5, 1871.

and figures of reference marked thereon.

Figure 1 of thedrawing is a representation of a side elevation of our invention. Fig. 2 is a perspective view, showing inner face of one hinge-lug. Fig. 3 is a section of the same. Fig. 4 is a section through entire hinge.

This invention has relation to school-seats; and it consists in the novel construction of the joint by means of which the seat is hinged to its support, so that when the seat is raised or let down it shall become graduallytightened, and thereby the jar and noise usually attending such operation will be prevented. In the accompany ing drawing illustrating this invention, A represents the end support of a school-seat, designed also to be the end support of a desk, toward the back part of which the seat is arranged to turn when not in use, and which constitutes the back of the seat when the latter is lowered for use. The seat is hinged to the arm a, and for such purpose has secured to its under side the hinge lug B. The end of the arm a is made with a corresponding lug, B, and both are pivoted together by means of a bolt, 0. The lug B is cast with a circular socket, I), through the center of which the bolt passes. In this socket a rubber washer, Z), fitting over said bolt, is placed, and on it a metallic washer, I), laid, and the nut I) turned 011 the end of the bolt against the latter. A similar socket, d, is formed in the inner face of the lug B, the bolt also passing through its center; and beside said socket a segmental recess, d, is provided. The face of the latter is made concave, so that it shall be deeper at its middle point than at its ends. A circular projection, d, on the inner face of the lug B, fits the socketdand turns therein, while a small stop, 0, at the side of said projection, enters the segmental recess d and fits it closely at either end, making the hinge tight at these points.

When the seat is turned the deepest part of the recess d. passing over the stop 6 allows the hinge to work loosely and easily; but, as either end of the recess approaches said stop-that is, when the seat is reaching its highest or lowest points of elevation or descent-the hinge becomes tighter, and in this way prevents the noise or shock which would occur with the use of the ordinary hinge. The movement of the seat is arrested by the contact of the stop 0 with the end of the recess.

The rubber washer bis employed to give elasticity to the hinge and prevent it from working too loosely or with a shaky rattling movement at the middle point in the recess cl or becoming too tight at the ends.

hat we claim as our invention, and desire to secure by Letters Patent, is-- The hinge or joint for school,seats, constructed with the segmental recess d having a concave face, and with the stop 0, and provided with the rubber washer I), substantially as and for the purpose described.

In testimony that we claim the above we have hereunto subscribed our names in the presence of two witnesses.

THOMAS A. GALT. GEO. S. TRACY.

Witnesses J AS. B. PATTERSON, J NO. PATTERSON. 

